A semiconductor memory is volatile or nonvolatile according to its operating characteristic. The volatile memory is a memory that loses data stored therein at power-off. The nonvolatile memory retains data stored therein even at power-off. Therefore, the nonvolatile memory is used to store contents to be retained regardless of whether a power is supplied.
A flash memory is a typical nonvolatile semiconductor memory device capable of implementing high integration and mass storage and is applied to a handheld electronic device. Other nonvolatile memories include a Phase-change Random Access Memory (PRAM) using a phase change material as a nonvolatile element suitable for a random access and for large capacity and high integration and a Magnetic RAM (MRAM) using a magnetic element. The PRAM and the MRAM may belong to a resistive RAM in that data stored in a memory cell is read out by measuring a resistance value between both ends of the memory cell. Operating speeds of the PRAM and the MRAM are faster than that of the flash memory.
In recent years, a semiconductor memory device that is formed of different types of nonvolatile memories (e.g., a NAND flash memory, a PRAM, an MRAM, etc.) has been researched to improve the performance of a nonvolatile semiconductor memory device. However, different types of nonvolatile memories use different data storing methods and different management methods.